It is known that portable data carriers, in particular chip cards such as (U)SIM communication cards or Internet chip cards, can serve as web servers. Accordingly adapted data carriers have a web server application and are used for example as an authentication proxy in order to establish secure Internet connections between a user and an Internet portal, for example for an online bank. The data carrier is located here as a proxy between a client, for example a browser on a terminal of the user, and an external server, for example a server of the online bank on the Internet. The proxy behaves as a server vis-à-vis the client, but as a client vis-à-vis the external server. Since there are securely stored on the data carrier an integrity-checked hyperlink to the Internet portal and confidential login data of the user, a secure sign-on of the user to the online portal via the data carrier is guaranteed.
In general, when a data carrier with a web server is used in such or a similar way, the total data traffic during an existing communication link between a terminal of a user and an external server takes place via the data carrier. In the case of large amounts of data to be transferred for example for graphical elements, this occasionally leads to problems with regard to the memory capacity of the portable data carrier and the attainable data transfer rate of data transmission from the web server via the portable data carrier to the terminal.
WO 2005/091107 A1 discloses a browser plug-in for a web browser which makes it possible to check URLs (Uniform Resource Locators) of web resources, such as web pages or web services, for security risks potentially emanating from the resources. For this purpose, the plug-in compares a URL transmitted by the browser, before the URL is resolved and the corresponding web resource loaded, with URLs in a list of putatively security-critical URLs (a so-called “blacklist”) and outputs a security warning if the transmitted URL is to be found in the list and thus to be considered a potential security risk. The list can be internally stored or be queried interactively by the plug-in via a database.
It is therefore the object of the present invention to propose a method for effectively providing data through a server on a portable data carrier for a terminal connected to the data carrier.